View clinical trials related to Anemia, Sickle Cell.
Filter by:Patients with sickle cell disease have abnormal hemoglobin (the protein in red blood cells that carries oxygen to the body). This abnormality causes red blood cells to take on a sickle shape, producing disease symptoms. Fetal hemoglobin, a type of hemoglobin present in fetuses and babies, can prevent red cells from sickling. The drug hydroxyurea increases fetal hemoglobin production in patients with sickle cell disease by making a molecule called nitric oxide. The drugs L-arginine and Sildenafil (Viagra) increase the amount or the effect of nitric oxide. This study will evaluate: - The safety of giving L-arginine or Sildenafil together with hydroxyurea in patients with sickle cell disease; - The effectiveness of L-arginine plus hydroxyurea or Sildenafil plus hydroxyurea in increasing fetal hemoglobin in patients with sickle cell disease; and - The effectiveness of L-arginine plus hydroxyurea or Sildenafil and hydroxyurea in lowering blood pressure in the lungs of patients with sickle cell disease. (Pulmonary blood pressure is elevated in about one-third of patients with sickle cell disease, and this condition increases the risk of dying from the disease.) Patients with hemoglobin S-only, S-beta-thalassemia, or other sickle cell disease genotype may be eligible for this study. Before starting treatment, patients will have a complete medical history and physical examination. All patients will take hydroxyurea once a day every day by mouth for at least 2 months. They will be admitted to the NIH Clinical Center to take their first dose of hydroxyurea, and will have blood drawn through a catheter (plastic tube placed in a vein) every hour for 6 hours for tests to determine nitric oxide levels. After discharge, they will return to the clinic once every 2 weeks to check for treatment side effects and for blood tests to monitor hemoglobin and fetal hemoglobin levels. After fetal hemoglobin levels have been stable for 2 months, patients will be admitted to the Clinical Center for their first dose of L-arginine (for men) or Sildenafil (for women). Again, blood samples will be collected through a catheter once an hour for 6 hours. If there are no complications, patients will be discharged and will continue taking hydroxyurea once a day and L-arginine or Sildenafil three times a day for at least 3 months until fetal hemoglobin levels have been stable for at least 2 months. Patients will return to the clinic for blood tests every week for 2 weeks and then every 2 weeks to monitor hemoglobin and fetal hemoglobin levels and to check for treatment side effects. Patients will have eye examinations before and during treatment. Some patients with sickle cell disease develop abnormalities in the blood vessels of the eye. Also, Sildenafil can cause temporary changes in color vision. Rarely, more serious eye problems can occur, such as bleeding from the eye blood vessels or damage to the retina a layer of tissue that lines the back of the eye. Patients will also have an echocardiogram (ultrasound of the heart) before beginning treatment, after hydroxyurea treatment, and after 1 and 3 months of combined treatment with hydroxyurea and L-arginine or Sildenafil to help measure blood pressure in the lungs. Patients who develop complications from L-arginine or Sildenafil may continue in the study on hydroxyurea alone. Patients whose fetal hemoglobin levels increase with the combination therapy of hydroxyurea and L-arginine or Sildenafil may continue to take them.
ICA-17043 is being developed for the chronic treatment of patients with sickle cell disease (SCD) in both adults and children. ICA-17043 is a potent and specific inhibitor of a channel in human red blood cells (RBCs) that blocks RBC dehydration. ICA-17043 is expected to inhibit RBC dehydration and thus should prevent or delay the sickling process. By reducing sickled cells, an improvement in anemia, a reduction in painful crises, and ultimately, less end-organ disease is anticipated.
To establish a link among Chlamydia infection, sickle cell anemia, and stroke risk.
To measure the variability in pain and response to pain in sickle cell disease, and to build multivariate models to explain both patients' pain and their response to pain, especially, utilization of health care.
This is a study to determine if oral arginine will increase nitric oxide in sickle cell disease (SCD) patients with acute chest syndrome (ACS). It will also assess the effects of arginine in the body and how the body uses nitric oxide in ACS.
To investigate a modified hematopoeitic cell transplantation (HCT) procedure for sickle cell disease that significantly reduces the toxicity of HCT, yet retains its therapeutic benefit.
This study will develop a national cord blood bank for siblings of patients with hemoglobinopathies and thalassemia.
This study will test whether inhaling nitric oxide (NO) gas mixed with room air can improve pulmonary hypertension (high blood pressure in the lungs) in patients with sickle cell anemia. Patients with sickle cell disease 18 years of age or older may be eligible to participate in one or more parts of this three-stage study, as follows: Stage 1 Patients undergo the following tests to determine the cause of their pulmonary hypertension: blood tests; echocardiogram (heart ultrasound); asthma test; oxygen breathing study with measurement of arterial blood oxygen levels; chest X-ray; lung scans; MRI of the heart; 6-minute walk test; night-time oxygen measurement while sleeping; and exercise studies. Stage 2 Patients have a detailed MRI evaluation of the heart and are admitted to the NIH Clinical Center intensive care unit (ICU) for the following test: A plastic tube is placed in a vein in the patient's arm and another tube is placed in a deeper neck or leg vein. A third tube is inserted through the vein into the heart and the lung artery to measure blood pressures in the heart and lungs directly. Following baseline measurements, three medications (inhaled oxygen, infused prostaglandin, and inhaled NO) are delivered for 2 hours each, separated by a 30-minute washout period. A small blood sample is drawn during the NO administration. Patients who cannot be treated with nitric oxide or for whom the treatment does not work may receive monthly exchange transfusions for 3 months. For this procedure, 3 to 5 five units of the patient's blood is removed and replaced with 3 to 5 units that do not have sickle hemoglobin. Some patients who do not respond to NO or exchange transfusions may receive an alternative therapy, such as oxygen, prostacyclin, L-arginine, bosentan or sidenafil. Stage 3 Patients remain in the ICU with catheters in place for another 24 hours. During this time they breathe NO. Lung pressures are measured every 4 hours and blood is drawn every 8 hours. They then stay in the hospital 1 more day for observation. Patients then breathe nitric oxide continuously for 2 months using a tank of gas that delivers the NO through tubes placed in the nose. They may do this at home on an outpatient basis or may remain in the hospital for the 2 months. Patients have an echocardiogram and blood tests every week and do a 6-minute walk test every 2 weeks....
The purpose of this study is to determine how often people with sickle cell anemia develop pulmonary hypertension a serious disease in which blood pressure in the artery to the lungs is elevated. Men and women 18 years of age and older with sickle cell anemia may be eligible for this study. Participants will undergo an evaluation at Howard University s Comprehensive Sickle Cell Center in Washington, D.C. or at the National Institutes of Health in Bethesda, Maryland. It will include the following: - medical history - physical examination - blood collection (no more than 50 ml., or about 1/3 cup) to confirm the diagnosis of sickle cell anemia, sickle cell trait or beta-thalassemia (Some blood will be stored for future research testing on sickle cell anemia.) - echocardiogram (ultrasound test of the heart) to check the pumping action of the heart and the rate at which blood travels through the tricuspid valve. Following this evaluation, a study nurse will contact participants twice a month for 2 months and then once every 3 months for the next 3 years for a telephone interview. The interview will include questions about general health and recent health-related events, such as hospitalizations or emergency room visits.
Nitric oxide is important in regulating blood vessel dilation, and consequently, blood flow. This gas is continuously produced by cells that line the blood vessels. It is also transported from the lungs by hemoglobin in red blood cells. This study will examine how this gas regulates blood vessels and blood flow in people with sickle cell anemia. It will also look at a possible benefit of using certain genetic information to compare the white blood cells of people with sickle cell anemia to those without the disease. Patients with sickle cell anemia and healthy normal volunteers 18 to 65 years of age may be eligible for this study. Candidates will be screened with a medical history, cardiovascular physical examination, electrocardiogram and routine blood tests. Participation of volunteers without sickle cell anemia will be limited to a single blood draw for genetic study. Sickle cell disease patients will undergo the following procedures: Patients will lie in a reclining chair during the study. After administration of a local anesthetic, small tubes will be inserted through a needle into the artery and vein of the patient's forearm. These are used to measure blood pressure and draw blood samples during the study. Forearm blood flow will be measured using pressure cuffs placed on the wrist and upper arm, and a strain gauge (a rubber band device) placed around the forearm. When the cuffs are inflated, blood flows into the arm, stretching the strain gauge, and the flow measurement is recorded. A small lamp will be positioned over the hand. Light reflected back from the hand provides information about nitric oxide and hemoglobin in the blood of the skin. A squeezing device called a dynamometer will be used to measure handgrip strength. Baseline blood flow, nitric oxide, hemoglobin, and handgrip will be measured after an infusion of glucose (sugar) and water. These measurements will be repeated at various times before, during and after administration of small doses of the following drugs: - Sodium nitroprusside - causes blood vessels to dilate and increases blood flow to the heart - Acetylcholine - causes blood vessels to dilate and slows heart rate - LNMMA - decreases blood flow by blocking the production of nitric oxide There will be a 20- to 30-minute rest period between injections of the different drugs. When the above tests are completed, the patient will breathe a mixture of room air and nitric oxide for 1 hour through a facemask placed over the face, after which forearm blood flow and light reflected from the hand will be measured. Then the patient will do the handgrip exercise for 5 minutes, after which blood flow and hand lamp measurements will be taken. After a 20-minute rest period (with continued breathing of room air/nitric oxide), L-NMMA will be infused again. The handgrip exercise, blood flow and hand lamp measurements will be repeated. The face mask will then be removed, and the tubes will be removed 20 minutes later. Blood samples will be collected at various times during the 5- to 6-hour study through the tubes in the arm. Some of the blood will be used to look at genes that make proteins involved in cell-to-cell communication, inflammation, and in making red and white blood cells stick to the lining of blood vessels.